Some average characteristics are determined for 136 moderate magnetic
storms with sudden commencements that occurred during the interval
1902-1945. The average storm field is resolved for different
epochs of storm time st into Dst, independent of local time, that is, of
longitude X , relative to the sun, and into DS, that depends on X , Part
DS is expressed in terms of harmonic components with respect to X ,
and like Dst, the amplitudes and phases of these components, are functions
of st and of geomagnetic latitude. They are determined, for each
of the three magnetic elements, declination, horizontal force, and vertical
force, at eight geomagnetic latitudes ranging from 80*N to 1°S. In
the first, and main harmonic component of DS, its variations with respect
to storm time differs notably from that of Dst: its maximum is
attained earlier and its decay is more rapid. The storm -time changes
of the smaller harmonic components of DS have been less fully determined.
The average characteristics of moderate storms are compared
with those of weak storms.The research reported in the document has been sponsored by
the Air Force Cambridge Research Center, Air Research and
Development Command, under Contract No, AF 19(604)-1732.
AF 19(604)-1732
AFCRC-TR-57-295
AD 117-256LIST OF TABLES -- LIST OF FIGURES -- ABSTRACT -- 1. INTRODUCTION -- 2. THE OBSERVATORIES -- 3. THE STORM-TIME VARIATIONS : 3.1 Dst in the Geomagnetic-North Component, Hgm ; 3.2 Dst in the Geomagnetic-East Component, Egm ; 3.3 Dst in the Vertical Force -- 4. THE DISTURBANCE DAILY VARIATIONS -- 5. THE FIRST COMPONENT OF DS -- 6 „ THE HIGHER HARMONIC COMPONENTS OF DS AND SD -- 7. COMPARISON OF Dst AND DS -- 8 „ CONCLUSION : 8.1 The Intensity Index of Magnetic Storms ; 8.2 The Dst Variations ; 8.3 The DS and SD Variations ; 8.4 Future Plans -- 9. ACKNOWLEDGEMENTS -- REFERENCESYe
